Thermal Visualization of Buried Interfaces Enabled by Ratio Signal and Steady-State Heating of Time-Domain Thermoreflectance

Cheng, Zhe; Mu, Fengwen; Ji, Xiaoyang; You, Tiangui; Xu, Wenhui; Suga, Tadatomo; Ou, Xin; Cahill, David G.; Graham, Samuel

doi:10.1021/acsami.1c06212

Cited by 28 publications

(13 citation statements)

References 38 publications

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“…22 Notably, such measurements do not require extensive probe calibration (as for other AFMbased measurements) 23 and do not require depositing a reflective transducer layer (as for TDTR and HT-TDTR). 13 Furthermore, while TDTR benefits from repeated measurement with different light modulation frequencies 24,25 to maximize the sensitivity; the variable thickness of the sample provides an intrinsic discriminant (see Supporting Information, note 6) that enables precise PTIR measurements of both η and G in a single map.…”

mentioning

confidence: 99%

High Throughput Nanoimaging of Thermal Conductivity and Interfacial Thermal Conductance

et al. 2022

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Thermal properties of materials are often determined by measuring thermalization processes; however, such measurements at the nanoscale are challenging because they require high sensitivity concurrently with high temporal and spatial resolutions. Here, we develop an optomechanical cantilever probe and customize an atomic force microscope with low detection noise ≈1 fm/Hz 1/2 over a wide (>100 MHz) bandwidth that measures thermalization dynamics with ≈10 ns temporal resolution, ≈35 nm spatial resolution, and high sensitivity. This setup enables fast nanoimaging of thermal conductivity (η) and interfacial thermal conductance (G) with measurement throughputs ≈6000× faster than conventional macroscale-resolution timedomain thermoreflectance acquiring the full sample thermalization. As a proof-of-principle demonstration, 100 × 100 pixel maps of η and G of a polymer particle are obtained in 200 s with a small relative uncertainty (<10%). This work paves the way to study fast thermal dynamics in materials and devices at the nanoscale.

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confidence: 99%

High Throughput Nanoimaging of Thermal Conductivity and Interfacial Thermal Conductance

et al. 2022

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“…And the ITCs of Ga 2 O 3 /SiC range from 20 to 100 MW m −2 K −1 . [87][88][89] Zheng et al [90] prepared polystyrene thin films/sapphire samples and evaluated the relationship of interface bonding strength and rotation speed in the spin-coating process. With increasing spin-coating speed, the interfacial bonding strength increases gradually, and the ITC increases.…”

Section: Van Der Waals Forcementioning

confidence: 99%

Bonding‐Enhanced Interfacial Thermal Transport: Mechanisms, Materials, and Applications

Zhang

Guang

Cao

2022

Adv Materials Inter

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Rapid advancements in nanotechnologies for energy conversion and transport applications urgently require a further understanding of interfacial thermal transport and enhancement of interfacial thermal conductance (ITC). Sandwiching an intermediate material between two materials has led to a new insight on enhancing electron and phonon transportation, and is enabling the possible regulation of ITC, which has attracted increasing interest over the past decades. Herein, this strategy is named as thermal bonding, following the terminology of mechanical bonding and electrical bonding in microelectronics. The authors systematically summarize the interfacial thermal transport enhanced by thermal bonding from the category of interfacial thermal transport mechanisms, thermal bonding materials (TBMs), related applications, and potential challenges. Especially, the influence factors of interfacial heat transfer are highlighted, from three points, including interaction forces (van der Waals force, hydrogen bond, covalent bond, and metal bond), electron density, and phonon vibration density of states. The authors also outline and classify TBMs into metal bonding materials, organic bonding materials, and inorganic nonmetal bonding materials. As a novel and promising interface science and engineering field, it is believed that thermal bonding strategy will provide scientists and engineers more inspiration to understand interfacial thermal transport and solve the interfacial thermal challenges.

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“…One of the existing challenges with GaN-based HEMTs is the limited maximum output power that is governed by increased channel temperature induced by localized charged carrier flow [6][7][8][9], which ultimately degrades device performance and reliability [10,11]. Diamond, which has the highest thermal conductivity among natural semiconductor materials, is of particular interest for integration with GaN devices because of its potential to dissipate heat within the channel of GaNbased HEMTs [12][13][14], thus enabling faster switching and improved HEMT device architectures.…”

Section: Introductionmentioning

confidence: 99%

Detecting buried silicon interlayers in GaN/diamond bonded structures

Triplett¹,

Graham

Hines

2023

Gallium Nitride Materials and Devices XVIII

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We present a new approach for detecting interlayers in gallium-nitride (GaN) semiconductor structures bonded on single or polycrystalline diamond. GaN-on-diamond is advantageous because it integrates and effective heat spreader into GaN devices, which is important for high power density operation. However, analyzing GaN/diamond interlayers can be difficult because of nonuniformity as well as atomic-scale roughness across the wafer. In this work, we studied GaN/diamond samples using Raman spectroscopy and employed adaptive principal component analysis (PCA) to explore silicon interlayer properties. For each GaN sample bonded to diamond, the presence of a silicon interlayer was confirmed using high resolution scanning transmission electron microscope (HR-STEM) and electron energy loss spectroscopy (EELS). For comparison, we collected Raman spectroscopic data at 25 °C (5 different locations across the wafer, 10 microns apart in each direction) using 10 Raman spectrum acquisitions at each location in the 300-800 /cm range. Raman spectra only show three distinct vibrational modes at ~482 /cm, ~568 /cm and ~735 /cm, associated with the external lamp, GaN E2 (high) and A1 (LO) phonon modes. When spectra were analyzed using adaptive PCA, results reveal buried information in the baseline pertinent to the interlayer, including the ~520 /cm (silicon) phonon mode as well as ~360 /cm, and ~760 /cm modes, owing to nanoscale nonuniformities. Improved analysis of ultra-thin silicon interlayers in GaN/diamond opens up new opportunities to examine the impact of growth/post-growth steps, carrier density, and structure for modeling thermal boundary conductance.

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Thermal Visualization of Buried Interfaces Enabled by Ratio Signal and Steady-State Heating of Time-Domain Thermoreflectance

Cited by 28 publications

References 38 publications

High Throughput Nanoimaging of Thermal Conductivity and Interfacial Thermal Conductance

High Throughput Nanoimaging of Thermal Conductivity and Interfacial Thermal Conductance

Bonding‐Enhanced Interfacial Thermal Transport: Mechanisms, Materials, and Applications

Detecting buried silicon interlayers in GaN/diamond bonded structures

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